The present invention is directed to a visual display system and more particularly to a visual display system which allows the positioning of selected portions of multiple images on a visual display unit, for example, a CRT display. Provisions are made for generating blanking areas on the screen which may serve as a background or as a border for the images. The state of the prior art of image editing and dynamic viewing of stored digital images is represented by U.S. Pat. No. 3,976,982 entitled Apparatus for Image Manipulation and by U.S. Pat. No. 4,070,710 entitled Raster Scan Display Apparatus For Dynamic Viewing of Image Elements Stored in a Random Access Memory Array. The present system finds particular utility in the banking area where it is desirable to compare the signature appearing on a check or other type of document with that contained on a signature card for purposes of verifying the authenticity of the signature. In the past, such verification has been made by clerks examining the actual check against the card and making a decision based on a comparison of the physical documents. In electronic banking, the checks themselves are not transmitted to the customer but are maintained in a central document storage file. The physical checks are scanned by an optical scanner to convert the image of the check into electrical equivalents, generally pulses. Through various electrical signal processes the electrical image is compressed to eliminate superfluous and/or redundant portions. Compression of the electrical signal is desirable in order to transmit the largest number of images in the shortest possible time without loss in image quality. The compressed image, prior to display, is decompressed and directed to an image display device such as a CRT display. At the issuing bank a teller may review the CRT display of the check and compare it against a signature card to determine the validity of the signature. The signature card may also be displayed on the CRT if so desired. In viewing large quantities of checks, during the normal work day, the background of the image display may cause fatigue in the viewer. Therefore, it is highly desirable to blank the image display in the area where images do not appear in order to minimize the harshness of visual contrast.